Typewriting machine



March 3, 1931.

' A. G. FfKURowsKl TYPEWRITING MACHINE original Filed July 1,- 192'?4 Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE ALFRED G. F. KUROWSKI, OF BROOKLYN, NEW YORK, 'ASSIGNOR T0 UNDERWOOD ELLIOTT FISHER'COMPANY, 0F NEW YORK, N. Y., A CORPORATION OF DELAWARE TYPEWRITING MACHINE Continuation ofapplication Serial No. 202,777, led July 1, 1927. This application led December 8, 1929.

. Serial No. 411,227. i'

The.present invention relates to cylindrical 'typewriter-platens, the object being to produce an inexpensive and simple construction to. furnish clear-cut type-impressions with av mlnimum noise.

According to the invention, which has been verified by a large .number of tests, sounddeadening felt-sheeting of a proper thickness tightly woundaround the platen-core and covered by a tight rubber-sleeve of the usual grade, is capable of affording quietness without allowing the surface ofr the- 4platen to be pitted. The degreeof tension applied to the felt is a matter of extreme importance. There is used a line grade of woolen felt which is characterized by its resiliency. The felt which is usedy in practice is originally substantially one-sixteenth of an inch in thickness. If wound up without tensioning, four plies of one-sixteenth of an inch felt would make a thickness of onefourth of an inch upon the platen-core. But such a platen would not prove satisfactory. According tol the present invention, a. when winding the felt, it is kept under very.

high tension, such that the four plies, which were originally one-sixteenth ofan inch thick each, will form a jacket which Jis about oneeighth offan. inch in totall thickness. Tension sufficient to accomplish such a reduction 'in thickness, will give the' desired result as to quietness vand eiciency Aof the platen..

Thisresult is not obtained if the windings are substantially less tensioned than above described; ,while if the windings are placed under much greater tension than described,

- thecompleted platen will be foundl not to' f giveas good results, in a typewriting machlne.

Upon this body offelt, vwhich is under` permanent tension, there is' placed a Wearing jacket of one of the softer grades of platenrubber,' which jacket is about ve thirtyseconds of an inch thickf; 'the total diameter because they being confused' with the fourths inches.

Machines havingv these platens have beenL adopted in large numbers in telegraph offices,

make excellent type-impressions, and are very quiet, thereby permitting the operator to listen to a message as it comes in over the telegraph wire, without clatter of the typewriting machine upon whichl he is taking down such message.

This is a continuation ofuny application,

Serial No. 202,7 77, led July 1, 1927.

Other features and advantages will here-- inafter appear.

In the accompanying drawings,

Figure l is a side elevation of the platen partly broken away.

Figure 2 is a transverse section.

Figure 3 is a sectional diagram illustrat-- ing the winding and stretching of the felt vupon the platen-core.

' The platen vincludes a cylindrical corefl,

preferably of Wood. `Around the core is highly tensioned, in a pluralityoiwindings, felt-sheeting 2 to act as a sound-absorber,

which in turn is closely iitted into the exterior wearing acket or .preferred hard-rubber shell 3.

This system of a stretched and tightly wound wrapping of felt-sheeting is glued in place at the beginning and the end of the feltwinding and produces a base for the exterior shell rigid enough to prevent indentations bythe impact of the type-blows and yet of suicient resiliency and" uietness.' In particular, 'a form o platen is preferred having one-sixteenth inch woolen felt-sheeting, four-ply, wound around a core of basswood, said core to be of one and one-fourth inch outside diameter and having a one-half inch axial bore! The felt, being stretchable to a certain extent-,f will form a sleeveto be of oneeighth inch in total thickness, while the/exterior platen-rubber-shell is made a thickness of about five-thirty-seconds of an inch. The platen then will be of about one and three-quarters inches outside diameter.

A woolen' felt will hold its 'qualities' iii-l denitely and does not pack under the hammering of the types. l

To serve as mountings for the platen-shaft 4 end-caps 5 are secured to the core l by screws 6 vandprovided with hubs ,7 to extendinwardly toA it into the hollow platen-core, while opposed hubs 8 with set screws v9 will serve tov tix the platen-shaft 4, which extends *through said hubs 7 and 8 and axially through tige platen-core 1. The end-caps 5 shield the e ds of the platen by covering up the longitudinal edges of the felt wrapping and by closing up against the hard-rubber jacket.

As labove stated, the high grade vwoolen-- felt sheeting is under permanent tensionon the core, the tension being such that the thickness of the felt is thereby reduced about onehalf from its original thickness, and this material, so tensioned is highly resilient, sound-absorbing, and durable.

At Figure 3 is shown diagrammatically the stretching of the eltto attenuate it as it winds on' the platen-core. The leading end of the felt web is glued and tacked to the core. The four windings, each of about one thirty-second of an inch in thickness, form an approximately cylindrical shell. The outer winding is glued and tacked in place, and cut off from the unused web. After the rubber jacket 3 is tightly fitted upon the windings 2,

the jacket is ground down to perfect cylindrical form and proper size.

Variations may be "resorted to within the scope of the invention, and portions of the improvements may .be .fused without others.

Having'thus described my invention, I

1. A platen for a typewriter including a rigid core of suitable material, a hard Wrapping built up of woolen-felt-sheeting in a plurality of layers tightly wound around said core and fixedv in place by gluing, and a hard wearing jacket closely fitted upon said wrapping, said sheeting under suiiicieiit tension to substantially reduce its thickness.

2. A platen for a typewriting machine, including a core of basswood, means for securing the same upon a platen-shaft, a hard Wrapping of sound-deadening material in the form of stretchable woolen-felt-sheeting wound around said core in a plurality of thicknesses and under sufficient tension to reduce its thickness materially and to form a smooth cylindrical resilient sheath, and a hard wearing jacket in the form of a tube closely fitted upon the felt wrapping. l

3. A platen for a typewritiiig machine, in cluding a rigid core, means for securing the sameJ upon a platen-shaft, a hard wrapping of'highly tensioned windings of sound-deademng material in the form of woolen-feltsheeting forming a plurality O15-thicknesses on'said core to form a smooth cylindrical sheath of predetermined hardness and resiliency,.and a thick walled wearing jacket in the form of a tube closely fitted upon the feltwrap ing. j ,a

4. cylindrical typewriter-platen for furnishing clear-cuttype-impressions and or reducing the noise of the type-blows, including a core, a multiplicity of stretched windings thereonY of lwoolen felt 'sheeting whose thickness is substantially reduced by extreme tension of winding, said sheetingA being sound-absorbing and being permanently un- -der circumferential tension upon said core j wound under high tension such that the felting is reduced thereby to about one-half in thickness, said elting being under permanent tension upon said core, and a wearing jacket of a soft grade of platen-rubber upon said felting.

6. A cylindrical typewriter-platen having a hard core and a jacket wound thereon, said jacket being high-grade woolen felting wound under high tension such that the felting is reduced thereby to about one-half in Y thickness, said elting being under permanent tension upon said core, and a wearing jacket of a soft grade of platen-rubber upon said felting, means being provided for attaching said felting to the core to maintain it permanently under such high tension.

7 A cylindrical typewriter-platen having a hard core and a jacket wound thereon, said jacket being high-grade woolen elting wound under high tension such that the felting is reduced thereby to about one-half in thickness, said felting being under permanent tension upon said core, and a wearing jacket of a soft gradeof'platen-rubber upon said felting, said winding forming a shell of about four plies which is one-eighth of an inch in thickness.

8. A cylindrical typewriter-platen having a hard core and a jacket wound thereon, said jacket being high-grade woolen felting wound under high tension such that the felting is reduced thereby to about one-half in thickness, said eltin'g being under permanent tension upon said core, and a wearing jacket of a soft grade of platen-rubber upon said elting,

saidwinding forming a shell of about four ness, and said rubber jacket being about five thirty-seconds of an inch in thickness.

9. A cylindrical typewriter-platen having a hard core and a jacket Woundthereon, said jacket being high-grade Woolen feltingwound under high tension such that the felting is reduced thereby to about one-half in thickness, said felting being under permanent tension upon said core, and a Wearing jacket .of a soft grade of platen-rubber upon said felting, said felt winding being drawn so tight as to maintain its elastic qualities indeiinitelyv and not pack under the hammering of the types upon the platen. Y ALFRED `G. F. KUROWSKI. 

